How can I use Edge Creasing with OpenSubdiv?
OpenSubdiv has not been completely implemented into Blender. It is currently only used for viewport playback speed for animators.

Official Document about it's implementation

Limitations
There are number of limitations which are not resolvable with the current OpenSubdiv release and current OpenGL profile of Blender itself:


Smooth normals aren't currently correct. This goes into limitations of GLSL level we can currently use in Blender and what OpenSubdiv can provide us. It's being worked on though with high priority.
No OSX support, Historically Blender is using rather old OpenGL API and OpenSubdiv is using OpenGL 4. This makes it impossible to make Blender working with OpenSubdiv on OSX due to policy from Apple which forces everyone to drop older OpenGL code if newer API is used in application.
No UV maps support in viewport. This limitation is caused by OpenSubdiv which currently doesn't have nice support of UV mapping evaluation on GPU and has no way to calculate UVs on CPU as well.
No generated coordinates support. Generated coordinates in blender requires calculation of undeformed mesh on CPU which makes it rather really complicated to use OpenSubdiv in such configuration because all it's data is on GPU.
Tools which requires having mesh on CPU (for example snap tools) will fail for OpenSubdiv mesh. This also includes areas like geometry primitive counter in the Info header.
Currently shading is limited to a single material only. This is easy to resolve from Blender side and will happen sooner than later.
Loose edges and vertices are not supported.
Auto split is not working yet
Loop normals are not supported yet as well